1. Field of the Invention
This invention relates to portable vacuum cleaners, and more particularly to a portable vacuum cleaner capable of generating steam for delivery to a surface to be cleaned.
2. Description of Related Art
Portable vacuum cleaners for cleaning solid or liquid materials are well known in the art and are often referred to as "wet/dry" vacuum cleaners. Conventional wet/dry vacuum cleaners are disclosed for example, in U.S. Pat. No. 4,821,366 to Levine, U.S. Pat. No. 4,924,548 to Touya et al., and U.S. Pat. No. 5,005,252 to Steiner et al. These devices typically include a motor driven fan enclosed within a housing for producing a vacuum to draw liquid and debris into a collection nozzle. However, conventional wet/dry vacuums are unsuited for cleaning stained fabrics, upholstery, or carpets.
Improvements have been made in wet/dry vacuum cleaners in an effort to increase their stain cleaning effectiveness. For example, U.S. Pat. No. 4,788,738 to Monson et al. discloses a portable vacuum cleaner having an internal cleaning fluid supply system disposed in a removable discharge head which includes a chamber for retaining the cleaning fluid, a spray nozzle for discharging the cleaning fluid to the surface to be cleaned, and a vacuum intake head for drawing excess fluid and debris into the vacuum. A vacuum blower unit is provided in communication with the discharge head for creating suction to draw the excess cleaning fluid from the surface and for pumping cleaning fluid from the spray nozzle. A similar vacuum cleaner is described in U.S. Pat. No. 4,930,178 to Monson et al. which incorporates a filter element for separating debris from the cleaning fluid which enables the cleaning fluid to be recycled for subsequent use. Often, however, it may be undesirable to apply cleaning fluids directly to fabric, upholstery, or carpets, because fading, deterioration or other damage may result.
It is desirable therefore, to provide a portable vacuum cleaner which is capable of generating steam for delivery to an area to be cleaned, which overcomes the disadvantages of the prior art by providing for both steam cleaning and normal vacuuming.